Wednesday, June 23, 2010

New Flat Roof Does Cometh - Replacing our MCM flat roof preview

We're doing it. It's been a long time coming, mostly left to procrastination, but finally busting through our priorities in the form of water dripping onto the floor, the flatness that is our roof will be no more. A crew is going to rip the entire roof off the house, down to the rafters. Before they do, let's take a look at where the roof condition is at, what the problems are, most likely what you're roof problems might be, and then examine what we're going to do. To start, we had the flue cleaned a couple weeks ago. Considering we're getting a new chimney cap, I thought this might be good to get out of the premptive way, plus it's a pleasant picture to start with.

Here's said chimney, and it ain't your regular size chimney that can have a cap ordered from most standard catalogs, our chimney is 12 friggin feet long. In the distance you can see our next door neighbor's red chimney cap. We are getting ours custom made to be similar, a 12' x 3' sheet of metal in the wind will need more braces = more cost. In the end it will save our chimney that currently leaks and needs some mortar work in the long term. We also having it painted grey with high temperature tolerant silicone alkyd paint, say that fast three times.

Okay, so as you can see in the next few photos we have issues. These shots are within a couple hours of some major rain downpours. First and most obvious, the water is just sitting on the roof, not draining. Basically the sun eventually evaporates the water puddles, or it rains again and the process starts over, pretty cool huh? We also have had way too many patches and too many seams. Nonetheless the major problem is insufficient slope to the drains. Water has infiltrated the many roof membrane layers, trapped, the roof is a big sponge.

We have a sloped section of roof that wins the championship of most roof layers in one area. It has four, the final layer being some lovely three dimensional shingles, which shouldn't be used in this low slope application, and can't really be seen for their Gened-up-ness. So what are we gonna do? Sit back and watch a professional contractor do a damn good job replacing the entire roof.

Here's the deal, after they rip all 3 of the existing roof layers off they will place R-19 batt insulation (the pink stuff) in the roof cavity, we have no insulation right now due to the experimental radiant ceiling heating system that's long since been abandoned. The new plywood deck will be 3/4" T&G glued and screwed to the wood structure. A tapered insulation system, sometimes several inches thick, will provide a minimum 1/8" per foot across the entire roof to our four existing drains. Heavy duty .060
EPDM reinforced black membrane will be adhered to the tapered insulation.

Since the existing redwood fascia is covered with Gened-up beige aluminum, this will be removed to expose the original redwood for remediation and painting around the entire perimeter of the roof. A level coping will cap the membrane to redwood connection. All of which will be dark grey to match our previous curb appeal work. At left is a great example of the poor workmanship of the last roofer where our sloped roof meets the flat roof. Remember this photo for the 'after' shot.

A few final shots sweeping the roof for one final look before things begin to make major changes. This will be the last time hopefully that I have to sweep off the roof and look like a crazy MCM homeowner. I plan to post our progress as work progresses. Actually the materials were delivered yesterday, which forced me to crank this post out. For a teaser of what's coming, check out CincinnatiModernation's facebook page and become a fan.


  1. This is a very exciting project. Should pay excellent dividends. I am very excited to see how it looks. Only question, have you considered spray foam insulation instead of standard batt insulation? I am somewhat of a green building aficionado, and it seems the consensus is that spray foam is truly the real deal. I actually had the roof of my 1940s cape cod spray foamed during my recent remodel and the difference it makes is truly remarkable. Whenever my wife tells friends about the project, she can't help by wax about the spray foam.

  2. Thanks Joel. We did consider the spray foam, but we need to retain an airspace above the batts as part of the construction methodology. Providing baffles across the roof to retain the foam to a certain depth is too much effort and next to impossible with the way the roof is being pulled up and replaced in phased areas. We have the batts in one room already, and it's made a tremendous difference. I will be providing some diagrams of the new makeup of the roof in posts to come.


  3. WOW! this will be cool to watch. Your a brave soul.

  4. We live in Hamilton and have a flat roof with lots of leaks too - would you mind sharing who your contractor is? We are still looking for a good one.

    Also have you considered Duro-Last? What do you think of it, and why did you choose the EPDM over that?

    Finally, just curious what the budget is for this project, if you wish to share....

  5. Marie, we are using Molloy Roofing to do the job. Duro-Last is a better material than EPDM, as it's a heat welded PVC application. PVC or KKE are the top materials for low sloped membrane roofs. We looked at TPO, but I understand it's having integrity issues. Black EPDM is most economical and the .060 reinforced stuff makes it a little closer to PVC quality. The budget is way too much to mention : )

  6. Awesome blog. This is Marie's Husband, Jeff. We have a VERY similar roof as you guys on our modern house. We've been deliberating for almost a year now about what to do with our leaky roof. Looks like we'll have to call Molloy and have them up to take a look.

    Good luck with the renovations! Please post in-progress photos.